When using internal combustion engines, in particular piston engines having only a small number of cylinders, for driving motor vehicles, irregularities in the rotational speeds are encountered which are caused by gas and inertia forces. Depending on the type of construction and operational characteristics of the engine, these irregularities are balanced out to a greater or less degree by a flywheel arranged on the engine crankshaft and the design of the crankshaft itself. In any case, however, the balancing effect achieved heretofore has been insufficient. Particularly heavy irregularities are encountered with the engine idling at low speeds, because in this condition the operation of the engine is particularly unstable and, in addition, any balancing inertia forces are lacking, except for the flywheel.
The irregularities make themselves felt in the form of torsional vibrations which are transferred to the transmission and the entire drive train. In consequence thereof, rattling noises are produced, specially by the positively locking transmission elements, such as gears and clutches, and these noises are transmitted to the outside through parts of the housing and body and are felt to be disagreeable and disturbing, and this in particular within the resonant ranges. Heretofore, it has been tried to counteract these phenomena by providing torsional vibration dampers within the drive train and by mounting the arrangement in rubber elements. To this end, it has been known to provide torsionally elastic elements in the driver disk of a clutch provided between crankshaft and transmission shaft. It has also been known to provide the crankshaft with damping elements which respond to and counteract spin accelerations. Usually, such damping elements are arranged at the end of the crankshaft opposite the end carrying the flywheel and the clutch provided with the torsionally elastic damping elements.
As has been mentioned before, the above-described known measures are only to a very limited degree capable of damping the torsional vibrations caused by irregularities in the rotational speed of the engine. The known damping elements are effective only within a limited vibration range. Especially in the case of low frequencies, their effectiveness decreases rapidly so that the disagreeable noise makes itself particularly felt when the motor is idling. These torsional vibrations and the noises resulting therefrom have to this date set insurmountable limits to all efforts aiming at reducing the idling speed of motor vehicles below the values presently regarded as normal, in order to save fuel.